Drawing reproduction



p 1947. R. J. WIRSHING El AL 2,427,938

DRAWING REPRODUCT ION Filed D90. 24, 1943 may? 4010 aria/war: diiJnm 3nmtors Ottomcg Patented Sept. 23, 1947.

2,427,938 DRAWING REPRODUCTION Ralph J. Wirshing and Frank E. Smith, Detroit,

Mich, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application December 24, 1943, Serial No. 515,622

(Cl. 250'l1) 4 Claims. 1

This invention relates to means for reproducing drawings of considerable size. As is well-known in the arts, where large structures are fabricated, such as in the automobile and aircraft work, it is often necessary to provide full size drawings of parts or assemblies. These drawings represent considerable work in their origin, and because of their size it is necessary to make them originally on some substantial backing so that they will not be injured by ordinary use, and also so that their dimensions will remain within proper tolerances with variation in temperature and humidity. These drawings have been originally applied to large sheet material, in some instances steel sheets of relatively thin dimension, and in order to produce prints or reproductions therefrom, various methods have been used, some involving the use of X-rays and others luminescent material activated by oruinary light. One method which has been used is to apply to a large steel, or otherwise opaque backing sheet, a layer of material acting as a vehicle for excitable fluorescent or phosphorescent material, and then marking on this layer with opaque lines to produce the drawings; next exciting this fluorescent layer and causing a sensitized sheet previously placed in contact therewith to be subjected to such excitation and thus reproduce the drawing. This excitation may be either by X-ray or by visible light. Another method has been to use a similar excitable under-coat and entirely cover the surface of the same with an opaque layer of lacquer base; then scribing in the upper layer to expose lines of the excitable or fluorescent surface and to obtain prints therefrom in the same manner,

In using this latter method, however, it has been found that the scribing tool in cutting through the opaque over-coat cuts down into the vehicle for the fluorescent layer and causes the same to chip or pull along and thus disturbs the clear-cut line that is desired. The vehicle for the fluorescent base which carries the pigment has hereto been of nitrocellulose base and is so hi h in pigment that the surface is rough and its strength reduced.

In order to provide a satisfactory surface, it is desirable to strengthen this vehicle so that it will withstand such force as applied by scribing and still not be caused to chip or tear at the edges.

It is therefore an object of our invention to provide a sufiiciently strong vehicle for the fluorescent pigment to enable scribing thereon.

It is a further object of our invention to provide a suitable under-coat surface in a complete body so that the under surface will not be damaged by scribing through the over-coat or upper layer.

With these and other objectsin view, the embodiments of our invention will be best understood by reference to the following specification and claims and the illustration in the drawing in which the figure shows in perspective a composite body in which original large size drawings may be inscribed.

Referring now more specifically to the drawing, there is first shown a steel backing sheet which may be of thin gauge material and of a. size commensurate with the size of the drawings which it is desired to make thereon. This steel sheet is first cleaned and then treated with an oil type primer so that a surface of paint or other material may properly adhere thereto. There is next applied a. layer of lacquer, varnish or similar substance acting as a vehicle for the luminescent or fluorescent pigment which may be barium chlorofluoride. As the vehicle, it is desired to provide some material which will form a hard surface so that any scribing which may project through an over-coat surface thereto will not tear or pull the material along.

As mentioned above, the ordinary nitrocellulose lacquer base has not been strong enough for this purpose due to high pigment content, and it is therefore proposed to use an enamel which will provide a harder surface. This enamel may be a modified one of alkyd and melamine resin which will act as a vehicle for the barium choloriiuoride or other luminescent material. This layer may be sprayed on as a relatively heavy coat and baked.

Over this base coat we may apply directly an opaque layer of lacquer having therein a certain color pigment which acts as the over-coat and in which the configuration or drawing outline may be scribed by cutting through to expose the upper surface of the enamel and the fluorescent material. This over-coat may have included therein a certain proportion of beeswax so that it may be readily cut by a scribe and also a pigment such as lead chromate to cut down X-radiation therethrough if X-rays are used. In reproducing this drawing, the sensitized sheet may be laid in juxtaposition to this composite sheet and X-ray excitation applied to expose the sensitized sheet. The drawing is then developed in the normal manner.

We have also found that the same problem may be treated by utilizing the same nitrocellulose lacquer vehicle for the fluorescent pigment and then applying directly thereto a layer of hard clear lacquer and as an example of the same, but in nowise a liimting sense, there may be used what is commercially known as half-second cotton solution. This layer on top of the highly pigmented layer below provides a sumciently hard surface for the opaque over-coat in which the actual drawing is made and protects the fluorescent surface from the scribing tool,

It will therefore be seen that we have provided means for producing thin accurate lines either by making the under-coat vehicle suificiently hard in itself or by covering the same with an intermediate hard layer so that the scribing of the upper surface will not interfere with the fluorescent or phosphorescent under-coat.

We claim:

1. A composite body for use in drawing comprising, a supporting sheet of material substantially unaffected by temperature and humidity, a layer of enamel having a luminescent pigment therein applied to one face of the supporting sheet, and a thin opaque coating over the layer of enamel in which a drawing may be inscribed.

2. A composite body for use in drawing, a supporting sheet, a layer applied to one face of the sheet comprising an alkyd and melamine resin enamel containing a luminescent pigment excitable by X-rays, and an opaque coating over the layer to totally cover the same so that a drawing may be inscribed in the opaque coatin which will expose the lines of luminescent surface and the hard surface of the enamel will prevent injury thereto by the scribin tool.

3. A composite body for use in drawing comprising, a supporting sheet, a layer applied to one face of the sheet consisting of a vehicle and luminescent pigment which may be excited, a transparent hard coating over the layer to protool: the same and an opaque over-coat on the transparent coating so that in inscribing a drawing in the opaque over-coat the hard coating will protect the layer, including the luminescent material, from injury,

4. A composite body for use in drawing compriisng, a supporting sheet, a layer applied to one face of the sheet consisting of a vehicle and a luminescent pigment which may be excited by X-rays, a coating of clear lacquer over the layer to protectthe same and an over-coat of opaque material capable of being scribed to form a drawing over the clear lacquer.

RALPH J. WIRSHING. FRANK E. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 25 Number Name Date 1,398,415 Fried Nov. 8, 1921 2,197,357 Widmer Apr. 16, 1940 1,625,416 Lilienield Apr. 19, 1927 2,303,942 Lane et al. Dec. 1, 1942 0 2,327,826 Sherwood Aug. 24, 1943 2,275,290 Dreyer Mar. 3, 1942 1,532,782 Sheppard et a1. Apr. 7, 1925 1,532,783 Sheppard et a1 Apr. 7, 1925 595,812 Kinraide Dec, 21, 1897 35 1,652,483 Knauss Dec. 13, 1927 1,565,256 Christensen Dec. 15, 1925 Certificate of Correction,

Patent No. 2,427,938.

September 23,

RALPH J. WIRSHING ET AL.

It is hereby certified that errors app correction as follows:

numbered patent I'BQlliilIl? read composite; column 3, u 1e 3, s llable priisng readpr'ts'mg; t ese corrections therein that th Patent Office.

Signed and sealed .this 2d day of December, A. D. 1947.

THOMAS F. MURPHY,

Am'atant Commissioner of Patents.

and then applying directly thereto a layer of hard clear lacquer and as an example of the same, but in nowise a liimting sense, there may be used what is commercially known as half-second cotton solution. This layer on top of the highly pigmented layer below provides a sumciently hard surface for the opaque over-coat in which the actual drawing is made and protects the fluorescent surface from the scribing tool,

It will therefore be seen that we have provided means for producing thin accurate lines either by making the under-coat vehicle suificiently hard in itself or by covering the same with an intermediate hard layer so that the scribing of the upper surface will not interfere with the fluorescent or phosphorescent under-coat.

We claim:

1. A composite body for use in drawing comprising, a supporting sheet of material substantially unaffected by temperature and humidity, a layer of enamel having a luminescent pigment therein applied to one face of the supporting sheet, and a thin opaque coating over the layer of enamel in which a drawing may be inscribed.

2. A composite body for use in drawing, a supporting sheet, a layer applied to one face of the sheet comprising an alkyd and melamine resin enamel containing a luminescent pigment excitable by X-rays, and an opaque coating over the layer to totally cover the same so that a drawing may be inscribed in the opaque coatin which will expose the lines of luminescent surface and the hard surface of the enamel will prevent injury thereto by the scribin tool.

3. A composite body for use in drawing comprising, a supporting sheet, a layer applied to one face of the sheet consisting of a vehicle and luminescent pigment which may be excited, a transparent hard coating over the layer to protool: the same and an opaque over-coat on the transparent coating so that in inscribing a drawing in the opaque over-coat the hard coating will protect the layer, including the luminescent material, from injury,

4. A composite body for use in drawing compriisng, a supporting sheet, a layer applied to one face of the sheet consisting of a vehicle and a luminescent pigment which may be excited by X-rays, a coating of clear lacquer over the layer to protectthe same and an over-coat of opaque material capable of being scribed to form a drawing over the clear lacquer.

RALPH J. WIRSHING. FRANK E. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 25 Number Name Date 1,398,415 Fried Nov. 8, 1921 2,197,357 Widmer Apr. 16, 1940 1,625,416 Lilienield Apr. 19, 1927 2,303,942 Lane et al. Dec. 1, 1942 0 2,327,826 Sherwood Aug. 24, 1943 2,275,290 Dreyer Mar. 3, 1942 1,532,782 Sheppard et a1. Apr. 7, 1925 1,532,783 Sheppard et a1 Apr. 7, 1925 595,812 Kinraide Dec, 21, 1897 35 1,652,483 Knauss Dec. 13, 1927 1,565,256 Christensen Dec. 15, 1925 Certificate of Correction,

Patent No. 2,427,938.

September 23,

RALPH J. WIRSHING ET AL.

It is hereby certified that errors app correction as follows:

numbered patent I'BQlliilIl? read composite; column 3, u 1e 3, s llable priisng readpr'ts'mg; t ese corrections therein that th Patent Office.

Signed and sealed .this 2d day of December, A. D. 1947.

THOMAS F. MURPHY,

Am'atant Commissioner of Patents. 

